Apparatus for exploding mine charges.



J. KRANNIOHFELDT. APPARATUS FOR EXPLODING MINE CHARGES. APPLICATION nun FEB. 19, 1907.

Patented Oct. 10, 1911.

2 SHEETS-SHEET 1- A Tram rm J. KRANNIGHFELDT. APPARATUS FOR BXPLODING MINE CHARGES.

APPLICATION FILED FEB. 19, 1907.

Patented Oct. 10, 1911.

2 SHEETS-SHEBT 2 JOEANN ICR-ANNICHFELDT, F COLOGNE, GERMANY.

APPARATUS FOR EXPLODING MINE CHARGES.

Specification of Letters Patent. Patented @mt, 16b,- IQTLL Application filed February 19, 907. Serial No. 358,174.

arate circuits containing the explosive charges. Such intermediate switches, however, were driven by clockwork, so that in exploding all the charges in a mine one is bound to the time of the clockwork. In order to overcome this drawback and to' enable the charges to be exploded at any desired intervalif necessary only after examining each circuitthe intermediate or local switch, according to my present invention, is controlled, adjusted or operated by electric means from a distant and therefore safe central station. For example, a

switch lever can be turned by a ratchet wheel and pawl driven by electric means.

from the central station. Any desired number of such local switches can be combined with a single central station.

In the accompanying drawings illustrating my invention Figure l is a diagram of the exploding plant, and Fig. 2, a 'plan of an intermediate switch on a larger scale.

Referring to Fig. 1, A is an electrically operated intermediate or local switch, B a switch provided at a central station and serving to operate the intermediate switch A, C a galvanometer, D the source of the high tension, and E the source of the low tension, electric current.

The intermediate switch,A (Fig. 2), inv

the example chosen, consists of a lever a onthe underside of which two springs b are secured, which, on the lever a being turned, connect the radially arranged contacts c. In order to turn the lever a, a ratchet wheel a is provided in which engages the pawl f attached to the lever e. The backend of the pawl f is guided by a pin it engaging in a groove g, so as to permit the pawl to properly engage the ratchet wheel as the lever is moved up and down. The lever e fulcrumed at g and carrying the pawl f, is so connected with the armature or core of an electromagnet that the return movement of the pawl takes place when the circuit is closed. In order to restrict the stroke of the lever, the pawl f is provided with a second arm, which as soon as the lever a arrives in the proper position, engages with the ratchet wheel 03 and prevents said wheel from turning further. Said lever e is guided laterally by the slot 5. By repeatedly raising and lowering the lever e, the ratchet wheel'd is continuously turned inthe same direction, the springs I) connecting the pins 0 in each position of rest of said lever, thus closing one of the circuits.

The switch B (Fig. 1) can be of any de sired construction, and, in the present case, is provided with three contacts is, Z, m,

whose connections will be clear from the foL' lowing description: Supposing the contact springs 6 0]? the distance switch A are in such a position that the circuit a provided with 6 charges 6 is switched in, the lever p is brought into contact with k, in order to closethe circuit 70, E, 9, contact springs b, chargecircuit n 7, C, 7s. The alvanometer shows the resistance of the c arge circuit n, so that the latter, when the number of charges is known to the operator, can be examined as to its accuracy. The lever 39 of the switch B is placed on contact Z, by doing which the circuit Z, D, E, 9, contact springs Z), local charge circuit a r, C, Z, is closed and the charge exploded. At the same time the galvanometer shows whether the explosion has taken place or not. Thereafter the lever 10 is turned into contact with m, in order to switch in the next local charge circuit a by means of the intermediate switch A. In this case the current passes over m, D, E, g, s, electromagnet h, t, m. The pawl f is in this case raised by the electromagnet h but of contact with the ratchet wheel and turns the lever a on falling; that is, after the circuit'has been interruptd. This has the advantage that on advancing the lever no spark is formed on breaking the circuit. Said switch can however also be so constructed that the lever a is advanced when the electromagnet is attracted.

The construction of the intermediate switch can be modified in any. desired manner.

ters' Patent is 1. In a centralized electric plant for exploding mine charges, the combination with What I claim and desire to secure by Leti a main hand switch, an electrically operated local switch, and charge circuits connected with said local switch, of a main battery, an auxiliary battery, a galvanometer, a circuit to connect said main and auxiliary batteries through said main hand switch with said electrically operated local switch independent of said galvanometer, a second circuit to connect said main and auxiliary batteries to said charge circuits through said main hand switch and galvanometer, and means to out said main battery out of said circuit, substantially as and for the purpose set forth.

2. In a centralized electric plant for exploding mine charges, the combination with an electrically operated local switch, and

-local circuits containing charges connected with said local switch, of a main circuit to operate said electrically operated local switch, a second main circuit, and two batteries adapted to be switched singly or together into said second main circuit, substantially as and for the purpose set forth.

3. A centralized electric plant for exploding mine charges, comprising in combination a three way switch at the central station, a main battery connected with two of the ways of said switch, an auxiliary battery connected with the thirdway of said switch, a galvanometer connected with said main battery through one of the ways of said switch and with said auxiliary battery through another way of said switch, a local switch for the clrcuits containing the charges, wires connecting said local switch with said main and auxiliary batteries through said galvanometer and through said switch at the central station, electromagnetic means to operate said local switch on operating said switch at the central station, and wires connecting said means with said main battery, substantially as and for the purpose set forth.

4. A centralized electric plant for exploding mine charges, comprising in combination a three way switch at the central station, a main battery connected with two of the ways of said switch, an auxiliary battery connected with the third way of said switch, a galvanometer connected with said main battery through one of the ways of said switch and with said auxiliary battery through another way of said switch, a local switch for the circuits containing the charges, wires connecting said local switch with said main and auxiliary batteries through said galvanometer and through said switch at the central station, an electro-magnet in close proximity to said local switch and electrically connected with'said switch at the central station, and a ratchet and pawl adapted to be operated by said electro-Inagnet to operate said local switch, substantially as and for the purpose set forth.

J OHANN KRANNICHFELIQT. Witnesses:

Bnssm F. DUNLAP, LOUIS VANDORY. 

